Tribology and ultrasonic hysteresis at local scales

Local adhesion hysteresis (AH) is difficult to measure using an AFM due to complications introduced by compliant cantilevers as they snap-in and snap-out to/from a sample surface. But, at ultrasonic frequencies well above the cantilever mechanical resonance, the effective stiffness can increase enormously. Therefore, ultrasonically vibrating a sample in contact with an AFM tip can probe the hysteretic cycle of tip-sample in- and out-interactions [Jpn. J. Appl. Phys. 32 (1993) 22; Acoust. Imag. (1996)] allowing AH to be investigated by measuring ultrasonic hysteresis (UH). For the first time UH is compared here with lateral force microscopy (LFM) data. The same kind of experiments is also implemented for a nanoindenter based setup. Thus, the micro- (nanoindenter) and nano- (AFM) scales are investigated. UH and friction of both length scales are found to be linearly related for surfaces differing widely in elasticity and adhesion. (C) 2003 Elsevier Science B.V. All rights reserved